The present invention relates to a tube bedding device, and more particularly to a device for covering drainage tubing with fine textured soil granules.
Subsurface drainage systems fabricated from corrugated tubes are currently playing a major role in land development and improvement. The advantages of corrugated drainage systems over the heretofore commonly used tile networks are quite numerous. The ease with which corrugated tubes are manufactured in continuous lengths together with the rather simple and inexpensive installation procedures are but a few factors which have contributed to the overwhelming commercial success of corrugated drainage systems. For the most part, such systems include main and lateral subsurface drainage lines comprising corrugated tubing, tees, wyes, couplings or connectors, and adaptors of one type or another. A typical system usually comprises a series of inclined lateral lines spaced from one another in parallel fashion on opposite sides of an inclined main line to which the laterals are conncted by either tees or wyes. The main and lateral lines may be quite long and therefore require the piecing together of various lengths of tubing. End caps are also needed to close the open ends of the main and lateral lines and thereby prevent the surrounding earth from entering into the drainage system.
Regarding the installation procedures, a trenching machine of one type or another may be utilized to dig the required trench. The tubing is then installed within the trench at the bottom thereof, and the trench is then backfilled with the soil initially removed. Generally, during the backfilling operation earth moving equipment is used to simply push the earth back into the trench. Large clumps of heavy soil are filled into the trench and the drainage tube becomes surrounded with these clumps. As a result, the clumps leave a large percentage of void volume which ultimately causes settling of the soil directly above the drainage tube. This settling crushes the tube and reforms the cross section thereof from circular to oval. Such ovalizing of the tube reduces the cross-sectional area thereof, and the load on the tube sometimes damages the tube.
On the other hand, when fine textured soil granules are utilized to bed the tubing, the void volume is significantly reduced. Little if any settling occurs, and the ovalizing of the tube is significantly reduced or completely eliminated. Also, bedding the tube in friable, high density soil provides a natural filter medium for the liquid flowing into the tubing during the drainage operation. Attempts have beem made to initially backfill the trench by manually breaking the clumps and then cover the tube with the thus formed smaller soil pieces. However, such a procedure is time consuming and not completely satisfactory.